Equipment And Method For Analysis Of A Fluid

Abstract

There is described an equipment and method for analysis of a fluid, suspension, solution, dispersion or fluid emulsion that automatically analyzes the characteristic properties of the samples of the fluids, such as paints, enamels, and dyes, among others, so that adjustments can be made to the fluid to meet the optical properties such as color, opacity, hue, saturation (tinting power), covering and luminosity, from the spectrometric measurement technique by transmission analysis of film having radiated fixed thickness.

Claims

1. A system for fluid analysis comprising: a control unit; a property measurement cell; a luminous source; and a spectrophotometer; wherein a value of a property of a fluid sample is analyzed in the property measurement cell; wherein the property measurement cell comprises an analytical chamber having a static optical window and a movable optical window between which windows a thickness of the fluid sample is defined by the control unit; and wherein the luminous source is configured to provide electromagnetic radiation to interact with the fluid sample for analysis by the spectrophotometer.

2. The system according to claim 1 further comprising: a first unit configured to contain a first constituent part of the fluid; a second unit configured to contain a second constituent part of the fluid; and a first combiner configured to combine the first constituent part of the fluid with the second constituent part of the fluid in a first ratio forming a first sample of the fluid, the first combiner controlled at least in part by the control unit; wherein the first sample is the fluid sample analyzed in the property measurement cell; wherein the first constituent part of the fluid is drawn into the first combiner via suction from a first pump located downstream the first unit and upstream the first combiner; and wherein the second constituent part of the fluid is drawn into the first combiner via suction from a second pump located downstream the second unit and upstream the first combiner.

3. The system according to claim 1 further comprising: a first unit configured to contain a first constituent part of the fluid; a second unit configured to contain a second constituent part of the fluid; a third unit configured to contain a third constituent part of the fluid; a first selector valve in fluid communication with the first, second, and third units, the first selector valve having a first rotating flange moved by a first rotary actuator, the first rotary flange presenting a set of first stop positions, the set of first stop positions having positioning controlled by the control unit and by first selector valve stops commanded by a first stop actuator, the first selector valve configured to receive at least a portion of the first, second and third constituent parts of the fluid; a dosing module in fluid communication with the first selector valve and configured to dose a volume of fluid for analysis, the dosing module controlled by the control unit; a second selector valve having a second rotating flange moved by a second rotary actuator, the second selector valve in fluid communication with the dosing module, the second rotary flange presenting a set of second stop positions, the set of second stop positions having positioning controlled by the control unit and by second selector valve stops commanded by a second stop actuator; and a mixing module in fluid communication with the second selector valve and comprising a mixing chamber in which the dosed volume of fluid is mixed upstream the property measurement cell; wherein the first selector valve presents a first stop position of the first set of stop positions that allows the admission of the first constituent part of the fluid from the first unit to an entry point of the first selector valve; wherein the first selector valve presents a second stop position of the first set of stop positions that allows the admission of the second constituent part of the fluid from the second unit to the entry point of the first selector valve; wherein the first selector valve presents a third stop position of the first set of stop positions that allows the admission of the third constituent part of the fluid from the third unit to the entry point of the first selector valve; and wherein the first selector valve presents a fourth stop position of the first set of stop positions that blocks the passage of fluid in all directions.

4. The system according to claim 3, wherein the spectrophotometer comprises a double beam spectrophotometer configured to provide electromagnetic radiation in a range from the ultraviolet to the infrared.

5. The system according to claim 3, wherein the property measurement cell further comprises mechanical cleaning arms coupled to pneumatic actuators activated by the control unit, the mechanical cleaning arms provided with elastomeric pallets for scraping one or more surfaces of one or both of the static optical window and the movable optical window.

6. The system according to claim 3 further comprising an optical calibration module commanded by the control unit, which introduces a set of neutral optical filters to the spectrophotometer, the neutral optical filters having known attenuation and fixed to a positioning block with position sensors and moved by pneumatic that introduce mechanical stops at positioning points of the neutral optical filters.

7. (canceled)

8. The system according to claim 1 further comprising: a first selector valve having a first rotating flange moved by a first rotary actuator, the first rotary flange presenting a set of first stop positions, the set of first stop positions having positioning controlled by the control unit and by first selector valve stops commanded by a first stop actuator; a dosing module in fluid communication with the first selector valve and configured to dose a volume of fluid for analysis, the dosing module controlled by the control unit; a second selector valve having a second rotating flange moved by a second rotary actuator, the second selector valve in fluid communication with the dosing module, the second rotary flange presenting a set of second stop positions, the set of second stop positions having positioning controlled by the control unit and by second selector valve stops commanded by a second stop actuator; a mixing module in fluid communication with the second selector valve and comprising a mixing chamber in which the dosed volume of fluid is mixed upstream the property measurement cell; and a fluid analysis module in fluid communication with the mixing module and comprising: the property measurement cell; the luminous source; and the spectrophotometer comprising a double beam spectrophotometer.

9. The system according to claim 8, wherein the analyzed property of the fluid sample is selected from the group consisting of color, opacity, hue, saturation, tinting power, covering and luminosity.

10. The system according to claim 8 further comprising two or more units, each configured to contain a constituent part of the fluid, the units located upstream the first selector valve; wherein the first selector valve is configured to provide the dosing module with a first ratio of the constituent parts of the fluid; wherein the value of the property of the fluid sample comprising the first ratio of the constituent parts is compared to a desired value of the property of the fluid sample; and wherein the control until controls the first selector valve to provide the dosing module with a second ratio of the constituent parts of the fluid such that the value of the property of the fluid sample comprising the second ratio of the constituent parts is closer to the desired value of the property of the fluid sample than the value of the property of the fluid sample comprising the first ratio of the constituent parts.

11. The system according to claim 10, wherein each constituent part of the fluid is drawn into the first selector valve by two or more pumps, one each located downstream each unit and upstream the first selector valve.

12. The system according to claim 10, wherein the two or more units comprise: a first unit containing a first constituent part of the fluid; a second unit containing a second constituent part of the fluid; and a third unit containing a third constituent part of the fluid; wherein the first selector valve presents a first stop position of the first set of stop positions that allows the admission of the first constituent part of the fluid from the first unit to an entry point of the first selector valve; wherein the first selector valve presents a second stop position of the first set of stop positions that allows the admission of the second constituent part of the fluid from the second unit to the entry point of the first selector valve; wherein the first selector valve presents a third stop position of the first set of stop positions that allows the admission of the third constituent part of the fluid from the third unit to the entry point of the first selector valve; and wherein the first selector valve presents a fourth stop position of the first set of stop positions that blocks the passage of fluid in all directions.

13. The system according to claim 10, wherein the dosing module comprises a dosing syringe and plunger, the plunger controlled by a linear positioner actuated by a motor; and wherein the plunger is configured to retreat until a volume of fluid for analysis is reached.

14. The system according to claim 10, wherein the mixing module comprises: a mixing chamber; a helical conical agitator; a motor; a movable wall; and a mover; wherein the helical conical agitator is located within the mixing chamber and connected to an axis driven by the motor; and wherein the movable wall defines one end of the mixing chamber and is driven by the mover.

15. The system according to claim 8 further comprising: a first unit containing a first constituent part of the fluid; a second unit containing a second constituent part of the fluid; and a third unit containing a third constituent part of the fluid; wherein each of the units is located upstream the first selector valve; wherein the dosing module comprises a dosing syringe and plunger, the plunger controlled by a linear positioner actuated by a motor; wherein the plunger of the dosing module is configured to retreat until a volume of fluid for analysis is reached; wherein the first selector valve is configured to provide the dosing module with a first ratio of the constituent parts of the fluid; wherein the property of the fluid sample comprising the first ratio of the constituent parts is compared to a desired property of the fluid sample; wherein the control until controls the first selector valve to provide the dosing module with a second ratio of the constituent parts of the fluid such that the property of the fluid sample comprising the second ratio of the constituent parts is closer to the desired property of the fluid sample than the property of the fluid sample comprising the first ratio of the constituent parts; wherein the analyzed property of the fluid sample is selected from the group consisting of color, opacity, hue, saturation, tinting power, covering and luminosity; wherein the first selector valve presents a first stop position of the first set of stop positions that allows the admission of the first constituent part of the fluid from the first unit to an entry point of the first selector valve; wherein the first selector valve presents a second stop position of the first set of stop positions that allows the admission of the second constituent part of the fluid from the second unit to the entry point of the first selector valve; wherein the first selector valve presents a third stop position of the first set of stop positions that allows the admission of the third constituent part of the fluid from the third unit to the entry point of the first selector valve; wherein the first selector valve presents a fourth stop position of the first set of stop positions that blocks the passage of fluid in all directions.

16. The system according to claim 15, wherein the mixing module comprises: a mixing chamber; a helical conical agitator; a motor; a movable wall; and a mover; wherein the helical conical agitator is located within the mixing chamber and connected to an axis driven by the motor; and wherein the movable wall defines one end of the mixing chamber and is driven by the mover.

17. A method comprising: analyzing with a fluid analysis module a value of a property of a fluid sample comprising a first ratio of constituent parts, wherein the analyzing comprises: defining a thickness of a testing portion of the fluid sample between a static optical window and a movable optical window; irradiating through the windows the testing portion of the fluid sample by a luminous source; and detecting the interaction of the fluid sample with the radiation by a spectrophotometer; comparing the analyzed value against a desired value; and preparing a second fluid sample comprising a second ratio of the constituent parts different from the first ratio; wherein the value of the property of the second fluid sample comprising the second ratio of the constituent parts is closer to the desired value than the analyzed value of the property of the first fluid sample comprising the first ratio of the constituent parts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 presents a schematic representation of the constituent modules of the fluid analysis equipment.

[0044] FIG. 2A presents a perspective view of the equipment that is the object of the present patent of invention and FIG. 2B presents a top view, evidencing the positioning of the modules.

[0045] FIG. 3A presents a perspective view of the selector valve (V.sub.sel1) and (V.sub.sel2); FIG. 3B presents a back view of the selector valve evidencing the pneumatic rotary actuator; FIG. 3C presents a back view of the selector valve evidencing the pneumatic rotary valve actuator and the four stop points; FIG. 3D presents a longitudinal sectional view; FIG. 3E presents a sectional perspective view of the selector valve body and the housing of the rotating valve head, having the channels for flow direction of the material to be distributed by the three distinct positions; and FIG. 3F presents the back part of the selector valve with the three connection entry and exit points.

[0046] FIG. 4A presents a perspective view of the dosing module (M.sub.dos), FIG. 4B presents a longitudinal sectional view and FIG. 4C presents the sectional details of the dosing volumetric syringe.

[0047] FIG. 5A presents a perspective view of the mixing module (M.sub.mist), FIG. 5B presents a longitudinal sectional view, FIG. 5C presents a perspective view with sectional details of the variable chamber in homogenization mode, FIG. 5D presents the detail of the variable chamber in the homogenization mode and FIG. 5E presents the detail of the variable chamber in the product expulsion mode.

[0048] FIG. 6A presents a perspective view of the fluid analysis module (M.sub.anflu); FIG. 6B presents a sectional view; FIG. 6C presents the sectional detail of the internal elements; FIG. 6D presents a sectional view of the reading chamber in the cleaning/product admission mode; FIG. 6E presents a sectional view of the reading chamber with the “optical windows” in the fixed analytical spacing for reading of the properties of the fluid that is being analyzed; FIG. 6F presents a top view of the inner part of the reading chamber presenting the centralized positioning of the “optical window” measurement and further the two cleaning pallets of the surfaces of the reading “optical windows”; FIG. 6G presents a perspective view of the measurement chamber; FIG. 6H presents a side view of the mechanical cleaning arm of the optical windows; FIG. 6I presents a perspective view of the mechanical cleaning arm of the optical windows and FIG. 6J presents sectional details of the interior of the cavity of the measurement cell with emphasis on the cleaning pallets of the optical windows.

[0049] FIG. 7A presents a perspective view of the optical calibration module (M.sub.cal), FIG. 7B presents a longitudinal sectional view and FIG. 7C presents the sectional detail of the internal elements.

DETAILED DESCRIPTION OF THE INVENTION

[0050] For the purposes of the present invention and in order to simplify, the expression “fluid for analysis” comprises pastes and/or pigment dispersions or mineral fillers; the expression “transparent vehicle and/or having controlled opacity” comprises a varnish and/or a mixture of solvents and/or resins and/or liquid vehicles with controlled opacity and/or combinations thereof, and may be presented in the context of the present invention as “vehicle”; the expression “analytical package” is used, for the purposes of simplification, to designate the mixture of fluid for analysis and the vehicle.

[0051] The equipment for analysis of a fluid that is the object of the present patent of invention, comprises a set of modules coupled in controlled series by a computer control unit (U.sub.cont) which comprises a programmable microprocessor connected to a microcomputer, which schematic representation is presented in FIG. 1.

[0052] The equipment for analysis of a sample of fluid, suspension, dispersion, solution of dyes or a fluid emulsion presents a first selector (V.sub.sel1) where the fluid to be analyzed, the vehicle, the solvent, respectively stored in containers (C1) and (C2) and (C3) are directed to the dosing module (M.sub.dos).

[0053] The containers (C1) and (C2) are provided with pumps (B) for recirculation, of independent activation, which pressurize the admission points of the first selector valve (V.sub.sel1) and that, consequently, feed a high-precision “dosing syringe” in the dosing module (M.sub.dos) by means of control of the computer system by the control unit (U.sub.cont) which, by means of algorithms, establishes the proportion between the fluid for analysis and the vehicle to be admitted to the interior of the dosing syringe of the dosing module (M.sub.dos).

[0054] The fluid for analysis and the vehicle admitted in the dosing syringe by suction, in a proportion that is pre-defined by the computer system, are dislocated to the mixing module (M.sub.mist) by means of moving the dosing syringe plunger by activating the motor of the linear positioner.

[0055] Between the dosing module (M.sub.dos) and the mixing module (M.sub.mist) there is provided a second selector valve (V.sub.sel2) which, in the transference operation of the components of the dosing syringe from the dosing module (M.sub.dos) to the mixing module (M.sub.mist), is switched by the control unit (U.sub.cont) to maintain the admission point in the “unblocked” position to allow the directional flow to the interior of the mixing module (M.sub.mist), returning to the “blocked” position upon conclusion of the flow transfer.

[0056] In the mixing module (M.sub.mist) the total load of the dosing syringe of the dosing module (M.sub.dos) (fluid for analysis+vehicle or “analytical package”), after being unloaded to the interior thereof, is homogenized in a mixing chamber having a helical conical profile rotor connected to a high-speed pneumatic motor, controlled by the control unit (U.sub.cont). Upon conclusion of the programmed mixing time, the total content of the mixing chamber is expelled to the interior of the fluid analysis module (M.sub.anflu) by means of the displacement of the movable wall (plunger type), of the mixing chamber, connected to a pneumatic actuator, controlled by the control unit (U.sub.cont).

[0057] In the fluid analysis module (M.sub.anflu) a film is formed of the homogenized fluid in the mixing module (M.sub.mist), said film being irradiated by means of a luminous source (F.sub.lum) and analyzed by a spectrophotometer (Esp), by means of the spectroscope technique by the transmission method, in the spectral region comprised between 100 and 6000 nanometers (from the radiation contained in the region of the ultraviolet to the radiation range contained in the infrared region), providing, in this manner, a precise determination of the characteristics related to the concentration and/or energy absorption index in the spectral region defined and/or transparency and/or covering and/or dyeing power (strength) and remaining colorimetric characteristic, providing information for adjustments of these properties.

[0058] For the calibration of the spectrophotometer, there is provided an optical calibration module (M.sub.cal) which introduces in the sample channel a set of “neutral optical filters” having known attenuation, which blocks part of the luminous radiation that reaches the detector of the spectrophotometer, avoiding the “saturation” thereof during the calibration phase. This methodology applied to samples having extremely high luminous radiation absorption (opaque liquids and/or highly filled with pigments or solid blocking particles) further foresees that, during the sample analysis phase, the attenuating filter is removed in an automatic manner, enabling the incident luminous radiation to have an extremely high intensity (multiplied by the filter attenuation factor), in this manner obtaining a quantity of radiation emerging from the sample in optimal energy levels for the detector, where the relation signal/sound is very low, propitiating in this manner measurements in optimal levels, where the measurement data collected by the spectrophotometer, by means of a subsequent mathematical treatment, are then divided by the “neutral optical filter attenuation index”, in each wavelength, obtaining in this manner the real transmission data, whereby the same may have extremely low values, however, with extremely high precision.

[0059] As presented in FIGS. 3A to 3F, the first selector valve (V.sub.sel1) presents a rotating flange (17) with movement executed by means of a rotary pneumatic actuator (12), said rotating flange (17) which presents four stop positions (14a), (14b), (14c) and (14d), having their positioning controlled by the control unit (U.sub.cont), where each stop position implies in a set of commands that are previously programmed by the control unit (U.sub.cont). The stop points (14a) and (14d), are regulable stops of the rotary pneumatic actuator itself (12), while the stop positions (14b) and (14c) are defined by stops that are commanded by two auxiliary pneumatic actuators (11).

[0060] In this first selector valve (V.sub.sel1), a first stop position (14a) allows the admission of the fluid for analysis deposited in the container C1 at the admission point (18a) of the first selector valve (V.sub.sel1), a second stop position allows the admission of the vehicle deposited in the container C2 at the admission point (18b) of the first selector valve (V.sub.sel1), a third stop position allows the admission of the cleaning solvent stored in container C3 at the admission point (18c) of the first selector valve (V.sub.sel1) and a fourth stop position promotes the blocking of the passage of fluid in all directions.

[0061] The admission of fluids at the admission point of the first selector valve (V.sub.sel1) is made by suction generated from the pressurization carried out by the pumps (B) of the containers C1 and C2.

[0062] The stop position that allows the passage of the solvent will be sufficiently detailed throughout the present specification.

[0063] At the beginning of the analytical process, the control unit (U.sub.cont), by identifying the first stop position (14a) by means of sensors installed in the rotary pneumatic actuator (12), aligns the exit from container C1 with the admission point (18a) of the first selector valve (V.sub.sel1), admitting the entry of fluid for analysis at the admission point of the first selector valve V.sub.sel1), in the proportion defined by the control unit (U.sub.cont), to forward the fluid for analysis to the interior of the dosing syringe in the dosing module (M.sub.dos). In the plunger (24) of the dosing syringe (25) there is provided a linear positioner (21) activated by a motor (20) which retreats said plunger (24) until the volume of fluid for analysis defined by the computer program installed in the processor of the control unit (U.sub.cont) is reached, the contents of the fluid for analysis being admitted, measured in an indirect manner by means of a linear transducer (23), connected to the plunger (24).

[0064] The control unit (U.sub.cont), by identifying the second stop position (14) by means of the spin of the rotary pneumatic actuator (12), aligns the exit of container C2 with the admission point of the first selector valve (V.sub.sel1), admitting the entry of the vehicle at the admission point (18b), of the first selector valve (V.sub.sel1), in the proportion defined by the control unit (U.sub.cont), to forward the vehicle to the interior of the dosing syringe of the dosing module (M.sub.dos). In the plunger (24) of the dosing syringe (25) there is provided a linear positioner (21), actuated by a motor (20) which retreats the plunger of the said syringe (24) until the volume of the vehicle defined by the computer program installed in the processor of the control unit (U.sub.cont) is reached, the content of the vehicle being admitted measured in an indirect manner by means of a linear transducer (23), connected to the plunger (24), in this manner completing the total volume of the syringe, named “analytical package” and having high volumetric precision.

[0065] When the fluids of the “analytical package” are being carried to the interior of the dosing syringe (25) of the dosing module (M.sub.dos), the control unit (U.sub.cont) maintains the stop position of the said second selector valve (V.sub.sel2) in the blocked position (14d), preventing the passage or leakage of fluid to the mixing module (M.sub.mist).

[0066] Once transferred to the interior of the dosing syringe (25) the components of the fluid formulation (analytical package), the control unit (U.sub.cont) activates the rotary pneumatic actuator (12) of the first selector valve (V.sub.sel1) until the fourth stop position (14d), totally blocking the passage of fluid to the dosing module (M.sub.dos).

[0067] When the passage of fluid to the dosing module (M.sub.dos) is blocked by the positioning of the first selector valve (V.sub.sel1) to the stop point (14d), the control unit (U.sub.cont) then positions the selector valve (V.sub.sel2), by means of the rotary pneumatic actuator (12) to the position of direct connection between the dosing module (M.sub.dos) and the mixing module (M.sub.mist), in a similar manner to the procedures previously described for the first selector valve (V.sub.sel1).

[0068] The control unit (U.sub.cont) then activates the motor (20) which dislocates the plunger (24) of the dosing syringe (25) forward, to expel the total contents of the “analytical package” stored in the interior of the syringe (25) towards the inner chamber (39) of the mixing module (M.sub.mist), which will be in the (expanded chamber) mode, as presented in FIG. 5D, whereby all this displacement of fluid is monitored by the linear transducer (23) connected to the plunger (24) of the dosing syringe (25).

[0069] Once concluded the dislocation of the plunger (24) of the dosing syringe (25), when the mixing chamber (39) of the mixing module (M.sub.mist) will be completely filled, the control unit (U.sub.cont) then switches the second selector valve (V.sub.sel2) to the blocked position (14d), as previously described.

[0070] The next step of the process is described as the mixing and homogenization phase of the “analytical package” in the interior of the mixing chamber (39) of the mixing module (M.sub.mist).

[0071] In this step, the control unit (U.sub.cont), after detecting the blocking of the second selector valve (V.sub.sel2), commands the pneumatic motor (30) which, by means of an axis (35) connected on one side to the pneumatic motor (30) and on the other side to a helical conical agitator (38), to effect the spin in high rotation for a pre-determined time interval, which time is sufficient to promote the complete homogenization of the contents of the mixing chamber (39).

[0072] Upon conclusion of the homogenization step, the control unit (U.sub.cont) commands the expulsion of the content of the mixing chamber (39) directly to the interior of the property measurement cell (49) of the fluid analysis module (M.sub.anflu).

[0073] This transference of the homogenized “analytical package” is carried out by means of the exit connector (34) of the mixing module (M.sub.mist) which connects itself by means of specific piping to the entry connector (41) of the fluid analysis module (M.sub.anflu).

[0074] During this cycle of transference to the interior of the fluid analysis module (M.sub.anflu), the control unit (U.sub.cont) will activate the mover pneumatic actuator (32), which is connected to the movable wall of the inner chamber (37) of the mixing module (M.sub.mist), moving it forward until all the content of the inner chamber (39) is expelled and transferred to the fluid analysis module (M.sub.anflu), as evidenced in FIG. 5E.

[0075] In this step, the helical conical type agitator (38) acts as a spring, being totally compressed without opposing or creating any restriction to the integral expulsion of the material contained in the mixing chamber (39).

[0076] In the subsequent step, the control unit (U.sub.cont) monitors the positioning of the interior of the analytical chamber (49a), whereby during all the transference phase, the analytical chamber (49a) must be in the expanded mode, according to FIG. 6D, and for this the pneumatic positioning actuator (45) must be completely retreated, allowing maximum spacing between the static optical window (46) and the movable optical window (47), not occurring any resistance of the fluid in totally filling in the reading cell cavity (49a), further expelling the sample of the “analytical package” of the previous analysis cycle.

[0077] After the conclusion of the transference of the “analytical package” to the interior of the analytical chamber (49a) of the fluid analysis module (M.sub.anflu), by the total contraction of the volume of the mixing chamber (39), as detailed in FIG. 5E, the control unit (U.sub.cont) commands the actuation of the pneumatic actuator (45) to the positioning of the reading optical windows (46) and (46) to the fixed measurement thickness, according to FIG. 6E.

[0078] After the confirmation of the positioning by the control unit (U.sub.cont), by means of the position sensors of this pneumatic actuator (45), the analytical procedure begins.

[0079] During the analytical characterization, the sample of the fluid material contained between the optical windows (46) and (47) is irradiated by means of the electromagnetic radiation produced by the luminous source (F.sub.lum) in the region from 100 to 6000 nanometers, being conducted by the optical fibers beam (44).

[0080] The electromagnetic radiation conducted by the optical fibers beam (44) then crosses the movable optical window (47), interacting with the sample of fluid for analysis contained between the optical windows (46) and (47) and emerging on the opposite side of the irradiation.

[0081] The product of the interaction between the electromagnetic radiation and the sample then crosses the optical window (46) and is collected by the capture optical fibers beam (43), being in this manner conducted to the double beam spectrophotometer (Esp).

[0082] The double beam spectrophotometer (Esp) in this type of application can be qualified for analysis from the ultraviolet range up to the infrared range (100 to 6000 nanometers), providing great analytical versatility for the equipment and analytical method described herein, generating information associated to the referred physical characteristic of the fluid which is forwarded to the control unit where the microprocessor processes the spectrophotometric measurements by transmission analysis which by means of the mathematical processing, presents the results of the analysis in the microcomputer.

[0083] During the next sequencing step, the control unit (U.sub.cont), must carry out the decontamination of the optical windows (46) and (47), before the next reading cycle, and for this purpose the control unit (U.sub.cont), will initially command the retreat of the positioning pneumatic actuator of the optical windows (45).

[0084] Once the position of retreat and the distancing of the optical windows is confirmed, by means of the position sensors of the pneumatic actuator (45), the mechanical cleaning arms (49), connected to the pneumatic actuators (40), will be activated by the control unit (U.sub.cont).

[0085] The mechanical cleaning arms (49) are redundant, and the pneumatic actuators thereof (40) provide a rotary scraping of the pallets (49b) manufactured from a special elastomer, which are conducted by means of the cleaning arms (49) over the surface of the optical windows (46) and (47).

[0086] The pneumatic actuators (40), activated by the cleaning arms (49) have an electronic interlocking cycle commanded by the control unit (U.sub.cont).

[0087] After this final step, the analytical cycle already previously described is reinitiated.

[0088] For the calibration of the spectrophotometer, there is foreseen an optical calibration module (M.sub.cal), commanded by the control unit (U.sub.cont), which introduces in the sample channel of the spectrophotometer (Esp), a set of neutral optical filters (56a), (56b) and (56c), having known attenuation, fixed to a positioning block (55), which block part of the luminous radiation that reaches the detector of the spectrophotometer, avoiding the “saturation” thereof during the calibration phase.

[0089] The movement of the “neutral optical filters” (56a), (56b) and (56c), is carried out by means of the pneumatic actuator positioner (50), there being possible the positioning of three cited neutral filters, there further existing two other auxiliary pneumatic actuators (54), which introduce mechanical stops in the positioning points of the “neutral optical filters” (56a), (56b) and (56c).

[0090] The position sensors (53) provide information as to the confirmation of the position of the “neutral optical filters” (56a), (56b) and (56c), to the control unit (U.sub.cont).

[0091] For the cleaning of the equipment and in order to clean the surfaces for analysis of a distinct product, the control unit (U.sub.cont) switches the second selector valve (V.sub.sel2) to the third position, allowing the admission of the cleaning solvent stored in container C3 at the admission point (18c) of the first selector valve (V.sub.sel1), and the second selector valve (V.sub.sel2) can also be activated for the passage of the solvent through all the equipment.